Ozone and climate change OR why complicated situations can lead to more appropriate solutions.

1 + 2 = 3. That relationship is easy to grasp and has a clear outcome. That is the kind of relationship we are taught to think in, in streight lines that we can predict with high precision. Such a relationship makes us feel secure and in charge. In contrast, we often feel unsafe if we cannot predict an outcome with high certainty.

Of course we all know that life is not easy and streight forward. Still, we often pretend that it is, disregarding the complex nature of life; disregarding the fact that other factors might come into play which we forgot, under-estimated, or did not know of before. This is true in our personal lives as much as in all other parts of life on earth. Such thinking becomes problematic when we avoid complexity and assume simple solutions where there are none. Because then we then miss out on solutions and opportunities that we do not recognize when considering just one part of the problem.

One of the more complicated systems of our earth is our climate. The complex interactions among various parts ensure that models are only rough approximations of reality that need constant refinements. This fact makes sense to those who are willing to accept complexity; but it is used to discredit science by those who assume simple streight lines.

Take for example ozone. Ozone is a greenhosue gas that is most prevalent in the stratosphere (the atmospheric layer at a height of about 10 to 25 km) where it acts as an important “sunscreen” for our planet: it filters out the part of sunlight which has high-energy wavelengths, and thus protects us from skin cancer and other health risks. During the last decades, ozone has been depleted severely over Antarctica, where the conditions are just right for a chain reaction in which chlorofluorocarbons (CFCs) break down ozone. These CFCs were commonly used as coolants and as insulation materials. Thanks to the Montreal Protocol from 1998, by now almost all ozone depleting substances are phased out and replaced by hydrofluorocarbons (HFCs) that do not react with ozone.

Many people believe that climate change is caused by the ozone “hole”. However, the ozone hole by itself has little to do with the increase in global temperature.  In fact, a depletion of the ozone layer should decrease global temperature, because a decrease in the amount of greenhosue gases should cool our planet. But the substances that cause ozone depletion (CFCs) are even more effective and much longer lived greenhouse gases than ozone, and thus more than counter-balance the cooling effect of ozone depletion. The net effect of the ozone hole is thus in fact that of warming. This warming effect is further increased by yet another unforeseen effect: the ozone hole contributes to the formation of stronger air currents above the southern oceans. These in turn cause deep CO2 rich waters to come to the surface, thus decreasing the uptake of CO2 by southern oceans. This in turn causes more CO2 to remain in the atmosphere, increasing global temperature.

Recently, it was discovered that the chemicals that are replacing the CFCs, the HFCs, are even more potent greenhouse gases than CFCs. By protecting the ozone layer we thus exacerbated climate change. Clearly, focusing on one problem (the ozone hole and the substances that cause it) separately from another problem (climate change), when they are in fact interrelated problems, can have unpredicted consequences. We  need to better integrate various problems and work on solutions that ameliorate all parts of a problem.

If we would accepted more complexity in our way of thinking, we might be able to find more effective solutions.

Maiken Winter

Further reading:

Guus J. M. Velders, G. J. M., Fahey, D. W., Daniel, J. S., McFarland, M., and Andersen, S. O. (2009). The large contribution of projected HFC emissions to future climate forcing. PNAS 106:10949-10954

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